Disposing food waste separately from other garbage is an important step in fighting climate change. Photo by Alec MacDonald.

For many Bay Area residents, an opportunity to fight climate change comes at least three times a day, as they choose what to eat and how to dispose of the leftovers. Even the most devoted member of the Clean Plate Club will leave a tangerine peel, a dirty paper napkin, or a chicken bone, and many people discard much more. If that organic waste gets shipped off to a landfill, it will decompose and create methane, a greenhouse gas which inevitably leaks into the atmosphere.

Methane traps heat far more potently than carbon dioxide, but it disappears more quickly from the atmosphere, which is why it is classified as a “short-lived climate pollutant.” Reducing the formation of methane in landfills can make an immediate, significant difference in combating climate change. The Bay Area Air Quality Management District has estimated that 51 percent of methane emissions in the region are generated by fugitive emissions from landfills; new survey methods give reason to investigate whether these emissions may be even higher than previously estimated.

Residents around the region have already been diverting some of their tangerine peels and paper napkins from landfills by using green waste bins, provided in many communities for collection of organic materials. Although some communities still collect only yard waste, many jurisdictions have implemented food waste collection programs, beginning with San Francisco in 1996.

However, a new state mandate will require everyone to make a more intense effort. Under 2016’s Senate Bill 1383 (Lara), agencies and jurisdictions involved in solid waste management must meet a goal of diverting 50 percent of organic waste from landfills by 2020, and 75 percent by 2025. Citing a recent study on California’s composting infrastructure, Robert Cave, an air quality specialist at the Air District, suggested that the Bay Area might need to double its composting capacity to meet SB 1383 goals.

Building new composting facilities or expanding existing ones may prove difficult in a region with expensive land and residents who worry about odor problems. Odor minimization is one of the targets of a new Air District methane emissions regulation, Rule 13-2, that will require best management practices for facilities. Along with methane reduction, operating procedures should also control both odor and volatile organic compounds, another source of air pollution. Cave explained, “If you compost 100 percent efficiently, you don’t have any methane — oxygen plus organics generate heat, and you get CO2 and water and humus. But if parts of the pile don’t get oxygen, that’s when you have problems, both methane and odor.”

In order to address air quality, Napa Recycling & Waste Services is moving from open-air composting to covered composting. The facility is expanding, but recycling manager Tim Dewey-Mattia said, “We have a small site, so we can’t get too large, and that’s true of other Bay Area sites as well.” His company plans to add an anaerobic digester with funding from a recent state grant. While more expensive, digesters take up less space than large compost piles, and can accommodate a waste stream with higher nitrogen levels from fats or meat. Dewey-Mattia reported that methane created during the process is fully captured and of higher quality than that recovered from a landfill, so it can be used as a carbon-neutral fuel for the vehicles operating at the recycling facility. However, digesters produce their own waste, he noted, citing as an example that “South San Francisco sends its [digester residue] to us because it still needs composting.”

Even expanding facilities will not enable the region to achieve SB 1383 goals without changes in waste disposal and collection practices, starting with the households and businesses that discard organic waste. Dewey-Mattia pointed out that rules for what to place in composting bins are probably easier to learn than for recycling bins, but they are also newer and vary from community to community because waste collection systems are very localized. “I’m confident that people will figure it out over time,” he said, explaining that when SB 1383 is fully implemented, waste collectors will collect a wider variety of organics, not just yard waste, and there will be a statewide uniform color code for waste containers.

In Alameda County, Rachel Balsley, a senior program manager at StopWaste, has been working on enforcing the county ordinance redirecting organic waste to green collection bins. For businesses and multi-family residential units, “twenty gallons of organics in the general garbage is the maximum we’ll allow, and they need to show that they have organics collection service,” she explained, adding, “For restaurants, compliance is also tied to their food permits.” Nudged by inspections, proper disposal of organic waste is improving. “We’ve demonstrated that all this is possible,” she reported.

For Balsley’s colleague at StopWaste, program manager Cassie Bartholomew, the goal is to prevent disposal in the first place. Bartholomew quoted some dismaying statistics: 40 percent of food produced in the US never reaches a plate, and in the Bay Area, 83 percent of organic waste comes from home or restaurant kitchens. She said that at her agency, “We look at the whole food cycle: how we purchase and consume food, food storage, using leftovers, and then composting what’s left.” The Stop Food Waste campaign includes helpful flyers, shopping list templates, and a website full of tips and tricks to reduce what goes into the compost bin. School programs help children learn techniques to practice at home.

StopWaste’s “Smart Kitchen Initiative” uses tracking technology to measure “pre-consumer food waste.” The agency offers restaurant owners assistance, from classes in knife skills that reduce waste in trimming meat, to education on how to determine whether food is still edible after storage, helping them minimize their waste and reduce spending on food that isn’t paid for by customers. Customers may see lower prices, or perhaps free soup with lunch when the restaurant wants to avoid dumping a surplus.

Finally, there is another option for many restaurants and cafeterias: donating food that is still edible but not usable in their kitchens. SB 1383 includes an edible food diversion goal of 20 percent by 2025, emphasizing the environmental benefit of donation programs that comes along with their social benefit. Two 2017 state bills have also made donations easier. Senate Bill 557 (Hernandez) expands on programs to share unwanted but edible food in school cafeterias by allowing schools to donate the surplus, while Assembly Bill 1219 (Eggman) protects those donating or rescuing edible food from certain liabilities.

At the regional level, the Air District’s senior environmental planner Chad White is working on an organics recovery initiative that will incorporate and build on the response to SB 1383. Green waste diversion can provide more value than just reduction of methane emissions from landfills, and any benefits, from marketable compost to biogas production, become incentives to keep the diversion programs healthy while keeping costs down.

White described the initiative as requiring a deeper collaboration between the solid waste sector and the Air District. It may also involve food and agriculture departments, because composting contributes to healthy soil and sequesters carbon, which helps offset climate change. To begin the process, the Air District convened a regional stakeholder meeting in June 2018 with participants ranging from solid waste professionals to environmental groups. Their challenge, according to White, is “how do we build new ways of handling organics without adversely affecting some air quality attainment levels, and also make the new approaches financially feasible and attractive?”

Meanwhile, methane reduction continues to hinge on critical choices made every day by individuals, whether they are a supermarket produce clerk, a restaurant chef, or a harried parent planning dinner for a young family. Success depends heavily on their ability to buy food wisely, use it well, and dispose of what is left responsibly.

Leslie Stewart covers air quality and energy for the Monitor.